During the Vietnam War there were allies that fought along side the US...

Question

They were not ARVN, but some type of local tribesmen. What were they called?

Answer 1

The various Montenyard tribes were almost always allies of the US forces.  The Green Berets, (US Army Special Forces) invested a lot of time and effort into winning them over to the US side and arming and training them.  The truth is that the "yards" as they were affectionately known, communally, hated and distrusted the lowland Vietnamese, and saw any help in defending their land and their way of life from lowlanders (NVA, VC or ARVN) as welcome.

Just so you know, there were also other US allies in Vietnam.  Both Australia and South Korea sent significant numbers of troops.  

Answer 2

Sounds like you're referring to tha Montagnards or the Hmong.

Cheers